A Mixed-Valent Pentanuclear CuII4CuI Compound Containing a Radical-Anion Ligand

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• 作者：Tiddo J. Mooibroek ; Guillem Arom ; Manuel Quesada ; Olivier Roubeau ; Patrick Gamez ; Serena DeBeer George ; Joris van Slageren ; Shadi Yasin ; Eliseo Ruiz ; Jan Reedijk
• 刊名：Inorganic Chemistry
• 出版年：2009
• 出版时间：November 16, 2009
• 年：2009
• 卷：48
• 期：22
• 页码：10643-10651
• 全文大小：897K
• 年卷期：v.48,no.22(November 16, 2009)
• ISSN：1520-510X

文摘

Reaction of 2,4-(2,2′-dipyridylamino)-6-(2-pyridylhydrazino)-1,3,5-triazine, abbreviated dppht (5), with copper(II) chloride in methanol yields a mixed-valent Cu^II₄Cu^I compound (6), also involving the presence of a radical anion. The single-crystal structure determination for [Cu₅(5^M)(5^MR)Cl₈] (6) reveals that the original dppht ligand (5) has been monochlorinated at one of its pyridine rings and oxidized at its hydrazyl moiety, generating the ligand 2,4-(2,2′-dipyridylamino)-6-(2-(5-chloropyridyl)azo)-1,3,5-triazine (5^M). Moreover, the molecular structure of 6 indicates that one of the two coordinated ligands 5^M is in a radical-anion state, symbolized as 5^MR, characterized by a typical N−N bond length of about 1.33 Å for a one-electron reduced azo group. The nature of this unique [Cu^II₄Cu^I(radical)] assembly is corroborated by X-ray absorption spectroscopy, electron paramagnetic resonance, and magnetic susceptibility measurements. Density-functional theory calculations are consistent with the unprecedented structural features and support the spectroscopic data.